Ask Dave 17: Power For Your Amateur Radio Station

[@arthurrourke4822]

It's never a waste of time watching this channel!

[@sorrycharlie3327]

Wow Dave, thanks for this video. There are a lot of HAM channels posting videos by people with limited knowledge. In the video I watched before yours, the narrator weakly attempted to explain linear power supplies & then placed a red balloon on the screen that reads "Hell I read it & I dont understand it." So much low quality information on youtube. Your video is a breath of fresh air. You give an excellent, understandable explanation of the electrical theory behind power supplies. You know what you're talking about & you are very good at explaining it! The information about the voltage range experienced by automotive & solar powered systems was especially useful. Fantastic video! I posted because the most recent comments are a year old & I want you to know that people are continuing to find your past videos & learn from them!

[@cougarhunter33]

The video answered my question perfectly. I just made General after 23 years of being a Tech. I have been out of the hobby for about 20 years though, and am just now beginning to assemble an HF station. My Yaesu FT-950 is on the way. I am a bit behind the times with equipment, because many years ago, switch-mode power supplies had a bad reputation of putting out noisy power. However, at our clubs field day, everyone there had one and they worked perfectly. Nice and light, too. I have a new-in-the box Astron RS-35M linear supply that I bought 10 years ago, and am considering basing the station on a QJE 50A switch-mode instead.

[@davecasler]

The Yaesu FT-950 is, I think, a 100-watt station, so that old Astron will work just fine and power a VHF rig at the same time. One hundred watt HF rigs really only need about 20 amps.

[@diamaunt2782]

What you described towards the end is a *boost* converter, buck converters always lower the voltage, boost converters raise them. And then there's the buck boost converter, that can raise or lower a voltage.

[@Jason-jd1jv]

Thanks for the video Dave. You answered my questions perfectly and then some. I appreciate all you do for us newbies who don't have Elmers yet. I'll definitely keep an eye out for all upcoming videos

[@randallbeckett2366]

Instablaster

[@11ildiko11]

Hi can you compare tube and solid state transmitter?

[@huey1111]

Dave, Thank You for giving back to the hobby.

[@MikeBerta]

Thanks Dave for this video. It really helped identify the right power supply and getting it hooked up. Local clubs just don't do the trick for me. These videos are a real help.

[@G5STU]

Great video , just shared it with a young newly licensed ham - covers all his concerns about shack and mobile power for his new FT891

[@Craines]

Very nicely done Dave. You have a great way of making difficult concepts easy to understand. Thank you.

[@davecasler]

+Craig Nessel Thank you!

[@graywolf1911]

Very informative Dave, good job ! And, I rode that line in May of 2010 from Durango to Silverton, one of the most scenic train rides we have ever been on.

[@jimawhitaker]

Hi Dave, really like your videos although I've been licensed since 1993. I have two Astron RS-35M's I've had powered pretty much 24/7 since I started the hobby. They've out lasted a wife and 3 homes ;-) keep the videos coming...

[@kg5tjv877]

WOW Jim! Thank you for that comment, I just purchased an ASTRON RS-35M Today to Power my YAESU FT-DX3000. I am a NEW HAM (General Class) and this is my 1st HF Rig. I wanted to purchase a Premium Power Supply in Hopes that it would be Kind to My HF Rig and hopefully few problems that would be related to Lack of Power. Knowing yours has lasted this long makes me Feel like I made a Great Decision. Thanks Again for the Post, You Made My Day Sir. 73 KG5TJV

[@joerogers4227]

I remember the "old" days with car radio's with vacuum tubes that required a B+ voltage higher then 12v dc. You had a vibrator that chopped the incoming voltage into a square wave that went through a transformer that had a higher output voltage that was rectified into a higher DC voltage, lets say 100 vdc that worked with tube technology.

[@jimmiller6933]

i always keep my dc power leads in the shack as short as possible o limit voltage drop. In my truck my transceivers and amplifier are mounted below the rear seat. I use 4 gage power leads to the battery, fused at the battery where I connect each device to the 4 gage with their power leads cut short but each radio has its fuse sized for the radio's needs. I also have 2, 150 amp relays under the seat so switches on the dash can control main power with another relay with another dash switch so I can turn the hf amplifier off when not working hf and also when tuning the antenna.

[@billdomb]

Great explanation of switching power supply!

[@petercharlesphotography7169]

The reason some supplies are variable are several. 1) Bench testing 2) some PA's such as the RM Italy amps require more than 13.8V to drive the amp to full output. 3) Long cable runs have DC loss or the operator is using a light gauge wire..again, DC loss when under load. Variable supplies are very useful. Switching supplies are notoriously known to produce RFI. Linear supplies do not. A well regulated and filtered switch supply are expensive.

[@azbrit2686]

Superb Job Dave as always.. I also rode the Durango Silverton train up and down the hill a few years ago. Beautiful part of the country.

[@jasonbrown467]

excellant video, i would like to point out that i thought buck converters step the voltage down and boost converters step it up, there are devices that can do both, but @21:33 the boost converter is labled as a buck converter. i could be wrong though. again, thanks for the video, i have learned a great deal over this past year from your videos

[@madsbahrt8222]

In the discussion of whether to discharge a battery all the way down to 11 V (at 21:34 in the video), it might be noted that it is a perfectly acceptable level for a 3 cell LiPO battery which also might be used with the buck converter.

[@davecasler]

The caution has to do with lead acid batteries. They don't handle deep cycles well. Even deep cycle batteries have a limit on the number of lifetime discharges. My suggestion is not to run down a lead-acid battery such that the rested voltage is 12 volts or less. That's about half discharge.

[@christiedawson440]

Thank you Dave! As a new HAM I am very hesitant to set up my first station due to lack of knowledge about powers and grounding. This was very helpful! I do have one question about the comment you made about your HT being damaged from an antenna. I am doing that now, but with a mag mount. Will this have the same issue? The mag mount is on a metal pole about 20ft high. Thanks!

[@Fishermanfred1]

Wow Dave, you have the best ham radio channel on you tube. Thanks for all that you do to help others in Amateur Radio. Fred

[@LyubomirStoychev]

Wow man, I love your videos, there aren't any other nearly as informative and spot on videos about ham radios as yours. Good work!

[@davecasler]

Thank you.

[@LyubomirStoychev]

So David, I purchased myself a Yaesu 8900R and have been looking for a way to power it. After watching your video I decided to build my own linear power supply which will be fairly cheaper than anything stock. However, I have a few questions. Could you confirm if I am in the right direction? Even though I calculated that an 11 VAC would probably be the sweet spot, I couldn't find anything more suitable in my local shops than 230 VAC / 11.5 VAC (RMS) at 150 VA transformer. Which after rectifying it would give the sqrt(2) or 1.41 * 11.5 = 16.215 VDC. Which of course is with about 0.3 volts above the 15.9 high margin. However I consider at least a 2 x 0.7 V drop due to the nature of the silicon diodes in the rectifier. Which brings the rectified voltage to about 15V . Now, add the resistance of cables, fuses and the voltage drop when the radio is in idle, can I assume that the design of this power supply would be safe to use? I've also roughly calculated that if a 8000 µF capacitor is added, when the radio at full power the voltage wil be dropping to around 12 Volts. Another thing, I think a 10000 µF capacitor would stabilize the voltage more, however it will introduce an about 12.5 Amps of current spike in the first cycle when the transformer is plugged in, would that be an issue?

[@LyubomirStoychev]

So, to sum it up, since you didn't reply, after days of research about power supplies in general, it turns out designing your own supply for a ham radio is trickier than I previously thought. First, I though I'd be OK with an unregulated linear power supply. However, even if you design your power supply at 15.9V, voltage can and probably will drop below 11.7V at some circumstances... Also it turns out some if not most radios won't be happy with a big 50/60 herz voltage ripple, unless you provide a huge huge cap, but then again a 50W radio at full load can easily surge up to 10A. Making your own regulator for a linear power supply isn't rocket science but then again you'd most probably end up with something with higher voltage to compensate for current, then regulate it down to 13.8, but then you'd probably want to implement an over voltage protection, in case your power transistor goes pop, or because of TVS, which again isn't rocket science, but complicates things a bit more. At the end you end up spending 60-70 euros for parts, at best. Some hours of work, which if you don't enjoy ... it's not worth. But even if you enjoy it, it is really important that you make this regulation and protection right, because you will be very sad if you toast your japanese high quality Yaesu... Switch mode power supplies are fairly complicated to make them yourself, modding a computer one is an option, but there is also a bit of luck there too. My final choice - I will just buy 1 switch mode, designed for a ham radio.

[@ivorbiggen9599]

Thank you Dave, very informative, that answered my next question didn’t even have to ask

[@garysiuco7834]

I must be a Nerd - I understood everything Dave said! Well done video Dave, it was a great refresher for an old guy like me. Thanks.

[@nelsonwalker7105]

i enjoyed this discussion i didn't know how switching power supplies worked

[@starlight1308]

Thanks, this was very informative. As a follow-up I'd love more information on how to figure out how long a radio can run on a given battery or how to pick the right size of battery for running your radio in emergency backup scenarios.Thanks again!

[@johnadams9558]

Hi Dave! Have you tried the TekPower TP30SWII? I haven’t tested it yet but I got it in part due to the noise and voltage knobs. I like the vehicle amp form factor but I intended it for the stationary test bench. I figured if it was set for mobility then added bonus for me but it needs the standard house plugs so unless I’m wired into the grid via camper circuitry then it’s not to mobile without a bunch of conditioning.......Er....I think?

[@packrat2569]

Oh! I just bought my first power supply and I didn’t realize how complex they can be. I’d better take another look at it, thanks Dave.

[@marinmarin7187]

I hear with a regular, hand-held radio repeater that is 115 km away. I am at an altitude of 9m and the repeater is at 1300m above sea level. How much power do I need in watts to connect to the repeater? With 5w handheld radio I hear great, but I can't connect. Antenna with 3db and 50w ?

[@DutchmanRadio]

I’d double your watts and get the nicest/highest antenna you can

[@txfotog]

Another awesome video Dave. Your last several videos have kind of followed along the progression I'm taking in learning the hobby. I had the same question as Jason about a month ago when I was researching & buying my first power supply for my first base/mobile rig, an FT-8900. I went with a 16A linear. (My rig manual says at high power...50W...it would draw 8-10W). Several people warned me against the noise of a switching PS. So I feel better about my choice after watching your video. I agree with Craig below. You have a great way of explaining things for us hams who weren't born with a a multimeter in our hand. Please keep up the great work! I rode the Durango-Silverton RXR as a kid on a family vacation back in the early 80's. And I believe with the pics I remember we have, it was Engine 482. That is BEAUTIFUL country up there. Great pic! 73! Michael M. WA5AZQ

[@NipkowDisk]

Excellent video. I'm quite old school and still insist on running linear power supplies because they are electrically quiet WRT RFI. Maybe I'll get a switching supply someday for mobile use, but I'll cross that bridge when I come to it. 73 DE N7LTH

[@MauriceCalis]

Hmm, I’m wondering if you were one of the administrators of my online Tech exam Wednesday. Studying for General now…was looking for a good breakdown on power limits at various frequency. I’m trying to spot the pattern.

[@WheezyE]

Hardware newb here. Is it bad for my equipment if I stack multiple ring connectors (for different devices: HF radio, VHF/UHF radio, antenna tuner, Antenna Switch relay) onto the same positive and negative 1/4-inch five-way binding posts on the back of my power supply?

[@davecasler]

No. No problem. Just be sure that the sum total power requirement at any given time is within spec for the power supply.

[@WheezyE]

@@davecasler Thank you and 73! KI7POL

[@Cheeseoverdose]

Been running my rigs off lipos and AGM batteries for about four years. No noise, runs even when the power is out.

[@davecasler]

My photovoltaic system uses AGM batteries. Works great. I changed the rig over to the Samlex power supply as part of the reference video series.

[@Cheeseoverdose]

David Casler I like the sound of that

[@sunnylandcamper]

Hey Dave, just wanted to say you have a few listeners here in the Peoria,Illinois area. I had just got an Antenna Analyzer and a buddy suggested I watch your Video (6M Tuning) low and behold I had already watched it.. we both agreed your Videos are great... Thanks and 73 KD9FQL

[@davecasler]

Thank you! I'm glad you find the videos helpful. 73

[@1911bladeguy]

I have that same powerwerx power supply. I had a question about the 14.1 volt rated supply, and you answered it perfectly. Actually another one of your vids helped me before this one. This video is way more comprehensive and more useful even than your other vid. This is a great resource. Thank you much Dave. 73 de KM4OVT

[@davecasler]

+Steve You're welcome!

[@jay-rus4437]

Thanks for the vids. Im in the civil engineering field by trade, and the analytical side of me wants to better understand these type topics. Im new to ham, just received my call sign 4 weeks ago, and have been curious about using mobile radios in vehicles, and even more curious about using equipment while supplying power from a 12v battery “go box”. So many are doing this, but also are using rigrunners that have an additional loss of 1v. That puts the available voltage at approx 11-11.7 volts. Once transmitting we would see another 1v or so drop. That 10-10.7v is getting way too low for my comfort level

[@N5ZY]

Once again Dave, great job! I continually refer our Technicians and Tech Students to your KZbin videos. For what it's worth on this topic, my Alinco DM330MV switching power supply has worked great. And I always suggest - if your power supply should have a max rating that is reasonably higher than your radio's max amperage. My 100 watt radio publishes 24 Amps max at 13.8 v, so I bought a 32 Amp switching power supply.

[@davecasler]

+Indiana Jones Thanks for your continuing support! My little PowerWerx SS30DV tops out at 25A continuous and 30A surge, which fits my radio nicely which requires 23A max.

[@AnirudhSharma1976]

It was of great help and knowledge,thanks Dave

[@mattkn4edg]

Dave, I was wondering about the amps needed to power my Radio Shack HTX-10 ten meter radio. I believe that it is about 80 watts. In the manual, it says to get at least 7 amps. I bought a 6 constant 8 surge supply, but think I will actually need much more, Like a 19 amp from radio shack.

[@davecasler]

I think the HTX-10 puts out less than that, but if it is an 80 watt version, you'll most certainly need more than 7 amps. I'm not familiar with the radio. You could try some Internet searches.

[@mattkn4edg]

Thanks! I just learned that it might actually be only about 30w max. I while just try out the power supply I got.

[@darinhitchings7104]

Excellent video. Thanks very much!

[@AlexGtheOG90]

Can I run shorter wire leads to the power supply instead of using the long leads?

[@bryanphelan1104]

GREAT shot of you and the 482 !

[@patrickslevin6424]

Hi Dave, got a serious question for you. I bought an 800 watt Generac Generator/Invertor a few days ago. I planned on using this unit for field day, unless I can quiet the IRF coming out of my radio's speaker it doesn't look like I'll be doing anything with it. Some back ground: Tried a whole bunch (6) torriodol ferrite fittings on the power line. Put more on my extension cords and more where the power supply plugs into my power line. If ferrite were the answer believe me I have plenty....still getting very loud noise. I did unhook my coax and the noise went away, I don't get any noise in VHF or UHF at all...it's all on HF (the bands in must use for field day) I move the generator around to the front of the house, I grounded the generator. In short, I've done everything I know to do to stop this noise to no avail. I've heard about a noise filter that might work but have no idea what I need or where to get it, can you help me? Thanks, Pat KD9DST

[@davecasler]

RFI from generators can be frustrating! It sounds like the generator is creating some amazing harmonics if they're being picked up by the radio. Check your power supply, maybe swapping it for another to see if it has any effect. Another option is to run the radio off a battery, and periodically recharge the battery. QST did a major review of generators in the June, 2012 issue, and there are some links there that may prove helpful. Good luck!

[@cougarhunter33]

Excellent question. One of our field day team had this very issue this year with his brand-new generator purchased for this purpose. He was pretty unhappy about it.

[@TheRealWeirdoC]

I love seeing your thousands of dollars worth of radio equipment sitting side-by-side with freebie multimeters from Harbor Freight. :)

[@davecasler]

:-)

[@fullwaverecked]

I've noticed that most vintage base stations plugged directly into the mains, but newer units require an external power supply. Why is that? Thanks!

[@allenmiddendorff2068]

Good Information, I need to review my mobile and station power.

[@davidbyrd5065]

You never fail to answer my questions. Thanks for the video. David Byrd KN4BHS

[@rangersmith4652]

I get the value of using an external DC supply for a transceiver because it's same when I build PCs; I'm used to selecting and installing an appropriate DC power supply in those. Doing so for my upcoming ham setup does not intimidate me. But when I build a PC for someone else, he or she never has to deal with that PSU because now it's inside the computer chassis, and from the user's perspective, only a 110-120V AC connection is required. So my question is, why does no transceiver maker include power conversion in the radio chassis? Is it RFI? Seems like shielding technology could manage that. And I get that a big honking DC supply can power more than one component (as in a PC), and I get that providing back-up DC power is far easier than back-up AC . But doesn't requiring a string of components tend to be off putting to potential new hams who just want to get on the air as simply as possible? And couldn't the same argument be made for antennas?

[@davecasler]

For many years some radios had their own internal supplies and some required an external supply. This is back when high voltage was needed for the tubes. Even my Yaesu FT-101B and FT-201 had internal power supplies. At some point the manufacturers stopped including them. Some amplifiers now include their own power supply, or are sold with companion supplies. Some high end HF radios come with internal power supplies. But most of us have to provide power separately.

[@thedashingstache5993]

Hello Dave, I am going to be picking up my first HF radio which will be and FT-891. Going to be going portable with it to the park and such, when connecting it straight to a battery will I need any sort of fuses or extra components to protect the radio?

[@davecasler]

The stock cable should have fuse holders already built in. If not, yes, you should put in a fuse. You can get automotive-style fuse holders at an auto parts store. If the rig puts out 100 watts, you probably will need a 25 amp fuse. Enjoy your portable operations!

[@thedashingstache5993]

Thanks for the quick reply.

[@josephroblesjr.8944]

Thank you for this!

[@30CalCoreLokt]

Dave! Thank you for your videos. I am very new to the hobby and have a question. I only have one quality 50w VHF radio. I'd like to put this into a portable chassis or go box so that I could use it in my vehicle, then move it inside for base station work. Ideally I'd like to have a battery large enough to power the radio for at least a few hours independently that I can also charge off of a cigarette lighter, charge with a trickle charger, or charge with a solar pannel. What battery would you suggest? Do I need a charge controller or battery management system? Thank you!!

[@3v068]

You could take advantage of the inefficiency of the linear power supply in cold climates.

[@Marty48034]

Well explained. This was great.

[@enzopulido2579]

Is it ok to connect 2 radios in 1 powersupply?

[@davecasler]

Yes. I do.

[@johnlaurin7022]

Thanks again Dave. Excellent.

[@NickBP0]

Hi Dave, I had a question about something you mentioned around the 6m30s mark, that the transceiver should be turned on after the power supply is on, and also that it should be turned off before the power supply is off. Why is that? Are supplies prone to unpredictable voltage when they're turned on/off, or are there other reason(s)?

[@davecasler]

Nick, the answer is that, yes, power supplies can put out spikes when turned on and off. But also the power dies away a bit slowly, so the rig is subjected to severe undervoltage which can make some of the circuits, particularly digital logic circuits, unhappy. Best to use the rig's power switch for power on and power off. 73

[@Mike82ARP]

Motorcycles, Solar power and HAM. A man after my own heart. 73 KM4UQU. Can more than one radio be hooked up to an external power supply provided the PS amp rating exceeds the requirements of the radios?

[@garretthatfield6246]

Hi Dave, another great video. I have a couple of questions. I see you have the SS-30DV in this video. How do you like it? I just bought the same power supply for my first HF rig. I've seen mixed reviews. The second question is what motorcycle do you own? I would love to see a video on what you are riding.

[@davecasler]

The PowerWerx SS-30DV works fine. It's not good for powering "tiny" loads, such as a QRP transceiver on receive; rather it prefers a somewhat bigger load. But as a power supply for an HF 100W rig, it does fine.

[@michaelbradley8508]

What type of bike do you ride? Is it equiped with a Ham radio? If so what type? Even if it is a hand held... VA6XMB

[@davecasler]

I currently have a 1994 Yamaha Seca II -- I am the original owner. However, it will go on sales soon. And, yes, I've operated 2m FM with it. My helmet has headphones and I connect them to the HT. I have a PTT switch on the handlebars.

[@lonestarprepper0156]

outstanding lesson thanks

[@johnayres9360]

Can i have 3 radios hooked up to a 35 amp Linear power supply.And have all three radios on but only talk on one of them at a time?

[@francismcclaughry3794]

I have to ask. why turn off the radio before turning off the power supply. the As-tron is not switching power supply. I have flipped the power supply of with the radio on. I have never had a problem. are you telling me that I will have a problem doing this. just urning it off using the power supply?

[@magicman08]

Shot in the dark. Bought a Kenwood ts-50 and a kenwood ps-30. My concern is the ts-50 appears to like a 20amp continuous power supply where the ps-30 is 15a continuous and 20 intermittent. Is this an issue?

[@davecasler]

The TS-50 should not need 20 amps continuously unless you're transmitting a full duty-cycle mode such as RTTY or PSK-31. I would still recommend a power supply that can deliver 20amps (or 25 amps) continuously.

[@magicman08]

@@davecasler I bought the ts-30 for $40. If that makes a difference. For the time being though, it will power the radio and tuner? I don't know if I'll even use hf much. What do you know about the ps-30? I read somewhere that it doesn't have over voltage protection? Is that a serious concern? I mean is it worth just spending $120-$200 on a power supply that won't fry my ts-50 and tuner? My logic is these would have been off the market if they were frying rigs on the regular though eh?

[@davecasler]

@@magicman08 I looked up both rigs and it looks like they should be a good match, particularly for SSB voice and for CW. If you try continuous duty cycle modes like RTTY and PSK-31, be sure to reduce the output power to about 50 watts or so.

[@magicman08]

@@davecasler thank you much for your time and effort in looking into this. Now that I know for the most part, that I'm over the power supply hurdle, I can focus on antennas. Going to watch your HF primer now. Great content and I like your video flow.

[@LowellMotel]

Dave, More info on your motorcycle activity please. Our local cult is vintage BMW's and we are new HAM's. Hope to see you one day! Thank You, 73! KD8WVY

[@davecasler]

Check out dcasler.com/motorcycling/great-places-to-ride/. It's a partial list of motorcycle videos I've done, all of them several years ago. Some of the earlier rides are just photos. 73, Dave

[@edwardgonzalez5817]

Dave can I use a small power supply with the icom756 pro

[@ethanpoole3443]

A few factual errors (such as mentioning buck converter instead of boost), but a 50% depth of discharge really is not a strain for *true* deep cycle batteries. The catch being to avoid hybrid type batteries that often carry labels like "marine deep cycle" as they are not true deep cycle batteries and will not tolerate a greater than 50% discharge without undo wear -- a good shopping guide is that no true deep cycle battery carries a Cranking Amps specification on its label. By comparison a true deep cycle battery can be safely discharged by up to 80% many hundreds of times (typically in the 500-1000 cycles range) without excessive wear. Shallower discharges will increase cycle life, but with 80% or less depth of discharge the increased cycle life tends to scale fairly linearly with depth of discharge, so you get more cycles, but you will ultimately run about the same number of watt hours through your battery whether it is, for example, 500 cycles at 80% DoD or 1000 cycles at 40% DoD -- one lasts twice as long but only delivers half the watt hours per cycle while the other lasts half as long but delivers roughly twice the watt hours per cycle, the same amount of useful life and power delivered either way (it does not scale perfectly linear, but it comes remarkably close). I think batteries tend to trip a lot of people up, especially when one gets into Peukert Effect constants and the impact they have on accessible lead acid battery capacity as the useful amp hours available to a load is entirely dependent upon the magnitude of the load and not a constant as many tend to believe -- a 230Ah battery with a 230A load will actually appear to be a 100Ah battery in terms of accessible capacity at such a draw rate, for example. My entire station, including computers, monitors, and lighting are powered from a bank of deep cycle golf cart batteries (6V@230Ah each) as I converted everything over to run off DC. I use a 13.8VDC DC-DC Boost Converter to feed my radios a stable 13.8V regardless of battery state and a 19V DC-DC Boost Converter to produce the power required for my dual 27" monitors, with added filtering where required to produce very quiet power from the DC-DC converters. An RV type smart charger (also RF quiet) then keeps the batteries topped up at all times whenever mains or generator power is available...otherwise I can run for days to weeks off battery power alone when required and it only takes about 4-5 hours to top off the batteries once depleted, so it does not require a lot of generator time, or fuel, to keep things running.

[@johnwmacdonald994]

Thanks Dave. Great discussion. And I'd like to take a ride in that train!

[@geraldshultz4271]

Good informative video Dave. Thank You.

[@KE8ODY-WV-Ares-Ham-Dad-3O4]

So a 30 amp switching supply would be enough for a icom 2730 mobile in the house? Or is that over kill

[@davecasler]

If that's all you have, it's overkill. But if you plan to add an HF rig, it's not.

[@jimmygerilius8494]

Hi Dave, I'm looking to power an old icom U16 (similar to O2-AT) portable radio UHF(5W) at home...440-450MHz. It draws about 1.5amp on HI power setting. Will a switching power supply interfere (RF noise) at UHF freqs? I'm looking at switching primarily for size, but if needed will do linear/bulker. Thnks.

[@francismcclaughry3794]

ok! can I install a 706 in my car?

[@edmundooliver7584]

for a Icom 7000 radio how many amps on a switch-mode supplies do you recommend.

[@davecasler]

25

[@angusmacwaters2956]

So it's called "Ask Dave". So I will ask Dave. I am 67 and suddenly become interested Amateur Radio. Maybe it has to do with all the antenna work I am doing at work these days (learning much as I go...learn from folks like yourself and other amateur radio enthusiasts). So how do I go about all the amateur radio stuff?

[@stevelucier8346]

The variable voltage will allow powering my hand held scanner at 9 volts!

[@Smobus]

Hi, 13.8v and 20A good for my yaesu ft 991a ?

[@susanthompson6881]

Dave…..In the past I heard that switching power supplies create noise in the HF frequency range but for VHF and above there is no noise problem from switching power supplies. Is there any truth to this assumption?………..Mark

[@jamescampos9358]

Hello,I have the MFJ-4035MV power supply, which was stored in a box for over 10 years. Previously it was working well. But now the voltage meter fluctuates and does not stay as set with the voltage adjustment knob.I did open the unit up to blow any dust in there but the problem persist.Can you tell me why this is happening?

[@davecasler]

Check with an external voltmeter to see if the output is actually fluctuating or if it's just the internal meter. If internal, you may have to retighten contacts inside. Note that line voltage is on some of the heat sinks, so unplug the power supply prior to poking around inside.

[@jamescampos9358]

@@davecasler Thank you very much Mr. Casler for the information. You make great videos, 73.

[@michaelbradley8508]

Dave - I am a regular subscriber to your channel and enjoy virtually all of your presentations. I just happened to play this older video of yours and am glad I did, it is great. You are a wonderful teacher. I have often wondered what you did as a career earlier in life. This particular video has a great deal of information in it that many HAMs, especially less experienced HAMs, may not grasp. People would be well advised to play this video several times to benefit from it. Please keep up the great work - you are a credit to the hobby. MB 73 VA6XMB

[@davecasler]

I was an electrical engineer before I retired, with lots of work in IT as well. My father was a teacher. I must've inherited the teacher gene! Thanks for the kind words!

[@adelarsen9776]

Yeah Dave but if you got a diesel quad you'd have much more torque...... Thanks for the great video. When I'm in the southern hemisphere I use an Emtron EPS 30. And oldy but a goody. In the north I use a Racal pvs-20 power supply.

[@Satchmoeddie]

+Ade Larsen Some local guy is selling 6 phase 28 volt Waukesha gen sets for less than dirt cheap. They came off cell towers & were used as aux power for when the batteries go dead from lack of sunlight on the solar system. I would need to rectify the 6 phase 28 volts then regulate it down to 13.7 then use an inverter to kick it back to 120 for those AC power needs. These Waukesha sets are propane/nat gas, & can be easily rejetted for either propane or natural gas. Every so often I do see an old military tri-fuel come up. Tri-fuel my ass! Try any fuel, other than diesel in one of those after it has been run with diesel & tell me how well that works, without cleaning the plugs.

[@Satchmoeddie]

+Seth B I just bought an Astron 35 amp & just I got a 1.2KVA buck boost 240/120 to 24/12 volt, a variable reglator, zeners, other passive parts, and a enough transistors to step that up to around 13.7 volts @ 100 amps peak, for about $300. I knew I kept those heatsinks around for a reason.

[@dalemyers9265]

i'm making a 500 amp switching power supply using a 2 farad cap.

[@okcafe86]

Very informative. I will be running my power supplies with a little more voltage now...I'm going with 14.4. Thanks for the knowledge.

[@RickRose]

You are an excellent teacher--Thanks!

[@davecasler]

Thanks!

[@bitogre]

FYI, the diagram at 21 minutes into your video is mislabeled. You say the right things but a switching power supply that boost power is called a "Boost converter". "Buck" converters are exclusive for dropping the voltage. You can fix this by simply changing "Buck" to "Boost" on that slide of the video. BTW, there are Buck-Boost converters (en.wikipedia.org/wiki/Buck%E2%80%93boost_converter) that will either boost or buck the voltage based on whether the input is higher or lower than the desired input. I just do not know if they are used in Amateur radio but then I doubt that they are needed for typical Amateur radio applications.

[@davecasler]

+bitogre Thanks for pointing out the error. Unfortunately, once I put up a video, KZbin won't let me edit it. Hopefully people will see this comment and check out the Wikipedia article. Thanks for your sharp eyes! 73, Dave, KEØOG

[@quaildogusa]

I’ve done 3 motorcycle trip on the “Million Dollar Highway “.

[@kansas7614]

Stupid question, I'm new to the radio world, I too have a Radio Shack 3A 12V DC power supply. My radio says 75 watts output on VHF and 55 watts output on UHF. I connected my radio to a SWR/Power meter. I have noticed that on VHF high power is only putting out 22 watts output and about 18 watts output on UHF.. So does your power supply affect your radio watt output? If so I need to get a better power supply to get better radio watt output?

[@davecasler]

I'm surprised your radios worked at all in transmit. You need a power supply that can put out 15 to 20 A. The power supply you have now is way undersized for your radios.

[@kansas7614]

Thank you David for your reply, Yes I did buy a new power supply, It is a 12 volt 30 amp and now doing testing my radio it putting out about to 92 watts on VHF 151.0000. and about 51 watts on UHF.I have the QYT 980 Plus. Thank you again.

[@lyfandeth]

Using two "good" meters in some tests, I found one was 0.2v off from the other, so I couldn't be sure of what the real 12? volt system was at. I built a dimple "10.000vdc" calibration source into an Altoids tin and calibrated them both. And the first free CenTech meter I got? Was off by 0.4V out of the box. Dave, you CAN'T assume uncalibrated meters are right. Build a calibration supply, or buy a Fluke, to judge all the others. As they age they all drift.

[@davecasler]

The statistical estimation of physical parameters makes for interesting science. The TekPower meter I'm using now seems to be within a couple hundredths of a volt. But two meters will never agree! If they're of comparable quality, just average the results.

[@lyfandeth]

Yes, each meter will have differences, sometimes just the random float of 2-3 digits in the least significant digit. But on a standard 4-digit meter set to the 2-20VDC scale, I find all four generally stay in agreement when I've calibrated both of them to "10.00" scale volts. Bearing in mind the calibrator is putting out 10.000 so there's no float of the last digit coming from that. I often throw out the LSD simply because that float can make it unreliable.

[@DHAtEnclaveForensics]

Hey Dave- Nice job, as always!

[@JamesEdwards780]

I am having trouble with the Math 13.8V * 20A = 276 Watts for a 100W Radio. What am I missing here?

[@davecasler]

The radios are 100 watts out. The output final amp is linearly biased, so the amp is less than 50% efficient. Hence the much higher power input.

[@johnwilbanks9595]

Can use a 30amp power supply on a 300 wat connex

[@davecasler]

No. Too small.

[@petenwood]

Dave, you are the Obi Wan Kenobi of Radio! I've learnt a lot from your channel. Also, I'm in the UK, so thanks for pointing out that other parts of the world don't run on 120VAC :-) M7 PNW

[@georgeknapp4909]

Just received my new mfj 4275 and I am lost. Don't know how to hook it up.Do I hook it to40amp 75amp or 35 amp?will there be a problem with having the power supply next to the Stryker 955 with 80 watts out put.

[@davecasler]

The 4275 has several power outlets, and you can use any of them if they are rated for the load. For example, a 100 watt SSB rig rarely draws more than 25 amps, and that only for very short periods. There is no problem putting multiple rigs on the same power supply.

[@michaelbradley8508]

That explains your great depth of technical knowledge. In some of your videos I've noticed you own a Ten-Tec radio. I'm currently in the market for a n HF rig and have contacted Ten-Tec about their OMNI VII unit. Apparently it is sold out and they are waiting for parts to begin production on the next run. Can you tell me anything about the radio? How does it compare to the more mainstream competition? Would you buy another Ten-Tec given the new machines on the market today? MB

[@davecasler]

The last I heard, TenTec was no more. Perhaps someone is going to revive the brand. Their Omnis were great radios. I replaced my TenTec Jupiter a couple years ago with a Yaesu FTDX-3000 and enjoy it thoroughly.

[@neilmartin112]

Very informative. Thank you.

[@christopherdarrough2667]

I got a astron power supply today says 7amps and 10amp continuous I hooked it to my 45 watt Kenwood nexedge Mobile Radio and the radio is set to key up to transmitt a status code it kicked the power supply Down and I couldn't get it to work went to power and on again kicked down the radio says 13.8v and 13amps guess it was to much for it so I ordered a 19 amp 13.8 switching power supply RadioShack one the Astron had transistors on the back I'm guessing it's a linear power supply makes me mad wish it would run my radio hope this 19 will

[@davidenglund]

Wow! Just Wow! Thx

[@peterkeyes4674]

Hi Dave, I ran across your videos on solar and saw the ham related video's. I know it's late in coming but just a little note. You're graphic with the battery and the DC-DC converter should actually be a boost converter, not a buck. Good video though, as are all the others I watched. 73 NU1W

[@AppalachianFreedom]

Great topic!

[@edvardgjertsen3939]

I have a question. What power supply should i get for a 65w 2m mobile kenwood?

[@davecasler]

Pretty much anything will do that meets the power supply requirements laid out in the owner's manual. I should think a 15 to 20 amp 12vdc supply should do. Make sure you get one designed for ham radio so that it has proper filtering.

[@edvardgjertsen3939]

David Casler Thanks!😃

[@CONFUCIUS-f2x]

Excellent.

[@ricknelson3607]

Dave I have a Beofang 5001 mobile unit. I had it on a 12v Solar system until I upgraded my solar to a 48v system. Now I am looking for a new power supply for my radio. Any suggestions?

[@davecasler]

Lots of people in your situation simply use a normal 120vac power supply that plugs into the inverter output, and power the rig from there. Hope that helps! 73, Dave

[@ricknelson3607]

Thanks, looking at TekPower TP30SWII 30 Amp DC 13.8V Analog Switching Power Supply with Noise Offset. Would like you thoughts.

[@davecasler]

Well, it certainly looks fancy! My fear with an adjustable voltage power supply is that I might bump the knob and change the output voltage without knowing it. For that reason I'd suggest a 13.8v-only power supply. That said, you may find uses for the variable voltage. It should certainly work. The frequency change capability might help, although all good amateur radio supplies are well-filtered enough that the harmonics of the switching frequency are not a problem. 73, Dave

[@ricknelson3607]

Thanks you so much for your thoughtful reply. Your videos are very informative.